Analyzing a building’s carbon life cycle in just one day
February 01, 2022
February 01, 2022
Quicker whole life cycle carbon impact assessment allows designers and engineers more opportunity to optimize design for carbon
This article first appeared as “A life cycle a day for better buildings” in Stantec Design Quarterly, Issue 14.
Whole life cycle carbon assessments are a bore—and an expensive one at that. Previously, these assessments have been tacked on to projects nearing completion to provide an indication of the carbon emitted by a building over its lifetime. These provide little opportunity for engineers and architects to optimize design for carbon and often rely on many hours of modeling.
But we are looking to change that with our new digital carbon workflow.
Whole life cycle carbon is the carbon emitted through the construction, use, maintenance, and demolition of a structure. Typically, we look at this carbon burden in stages such as production and consumption, use, operations, and end of life. When it comes to assessing the total carbon burden of a project, each of these stages requires us to use a different set of parameters and a separate method of calculation. This process can get quite complicated.
Traditionally, we look at reducing carbon appetite of buildings during the operational stage—through more efficient lighting, air conditioning and heating, and vertical transport. But the other stages—the production of building materials, the construction of a building, and its demolition—all make up a significant portion of a building’s carbon cost. We call this embodied carbon, and it makes up about 28% of the carbon emitted by typical new building.
As grid decarbonization continues across the globe, we expect that operational carbon emissions will decrease while embodied carbon emissions will come to make up about 40% of a typical structure’s lifetime emissions. Consequently, embodied carbon is an area where designers and engineers can make big sustainability wins.
There’s an emerging global consciousness around whole life cycle carbon, particularly in the regions where we work. Currently, 11 nations—including the United States, Canada, the United Kingdom, and several in the European Union—have standards dictating the assessment of whole life cycle or embodied carbon. In the US, Colorado just passed legislation more stringent than what is required by federal policy. This is particularly relevant in the UK at present as the Greater London Authority has mandated Whole Life Cycle Assessments (WLCAs) be submitted with planning applications at the outline planning stage and the detailed planning stage. WLCAs will have future relevance in North American as embodied carbon gets more attention and more jurisdictions pass Buy Clean legislation.
It’s also the right thing to do. It gives our designers and engineers opportunity to design with the future health of our communities in mind. It also gives our clients a clear picture of their carbon impact early in the design process.
Current industry practice makes it difficult to design with whole life cycle carbon in mind.
But current industry practice makes it difficult to design with whole life cycle carbon in mind. The standard approach in the industry is to take a project, push it through to detailed design, and run that model through industry-standard analysis programs. Those programs spit out some data on carbon life cycle that is inaccessible to anyone but the experts.
Consider for a moment a project we’re working on for Belmont Street in London. It’s a 3-building residential block with a combined 22 stories and 12,200 square meters (130,000 square feet). To get the project design to the point where we can accurately assess the embodied energy of the building, we had to expend 110 hours of modeling and a similar number of hours in engineering. Once complete, we run it through the software that creates a document in the format required by the Greater London Planning Authority—a utilitarian data table.
From this desperation came inspiration. We saw the opportunity and the need for a workflow that enables us to assess whole life cycle carbon from the very beginning of a project—while designers and clients still have options and decisions to make.
In this new digital methodology, we can spend just a few hours modeling a project from its most basic, two-dimensional massing plans and create something from which we can carry out a digital whole life cycle carbon assessment. From this model, we take just a few arguments—building use type, the area and the height of the building—and using our custom tool, our team can quickly compare the impact of design decisions on the construction’s carbon emissions. At Belmont Street—with just four-and-a-half hours of modeling and some time in our whole life-cycle carbon calculator—we can compare framing material, floor sizes, and even architectural build-ups. We can assess, change, and optimize all these factors before a column has been sized.
As engineers, we now have a direct link between design decisions and sustainability outcomes. And not only can we produce the required report, but we can also create a sleek, dynamic, mobile-friendly, and interactive document that shows clients how they can reduce their carbon footprint and how their design decisions influence sustainability.
Importantly, we can do this all in a day—from massing model through to report—in 7.5 hours. Previously, this process took three days of modeling time and another half day using the premiere whole life cycle assessment software. This new workflow allows us to design with community in mind and achieve lower carbon buildings for our clients, all with 50% less effort. That’s a clear win-win.
We’ve used this workflow on several projects. Now, we’re even applying whole life cycle analysis for master planning projects such as Pudding Mill Lane. There, we’re completing a life cycle carbon assessment at the master planning stage for 17 buildings by the River Thames.
This is a huge site, and the client is targeting 15% reduction in embodied energy from conventional. Previously, it would have required an immense mobilization of resources to put a project of this scale through structural design work and many hours of design and modeling before we could process it through traditional software. Instead, we have synthesized the architect’s model with our digital whole life cycle carbon workflow and created something fantastic—an interactive report that encompasses all 17 of the structures on site. With this report we can guide our clients through the project, structure by structure, and demonstrate where they can make sustainability wins. We can show them just how much carbon they can save; we can show them how it can be done, and we can even show them where in the life cycle of the structure their savings will be realized. In short, we have taken the boring and made it brilliant.
With this workflow, analysis, and reporting power, we can better assist clients with whole life cycle assessments.
This innovation, and the immediate feedback it provides, will begin to create an intuition in our engineers around embodied carbon and what efficient design for embodied carbon looks like. By conducting these assessments when design changes are still possible, Stantec engineers can give clients more options and help deliver projects to clients that are more carbon friendly.
The clearer the picture we have of a building’s carbon over its whole life cycle, the better we can design for the low carbon futures of our communities.